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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:19:13 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:19:13 +0000 |
commit | 218caa410aa38c29984be31a5229b9fa717560ee (patch) | |
tree | c54bd55eeb6e4c508940a30e94c0032fbd45d677 /tests/ui/nll/issue-27282-mutate-before-diverging-arm-2.rs | |
parent | Releasing progress-linux version 1.67.1+dfsg1-1~progress7.99u1. (diff) | |
download | rustc-218caa410aa38c29984be31a5229b9fa717560ee.tar.xz rustc-218caa410aa38c29984be31a5229b9fa717560ee.zip |
Merging upstream version 1.68.2+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tests/ui/nll/issue-27282-mutate-before-diverging-arm-2.rs')
-rw-r--r-- | tests/ui/nll/issue-27282-mutate-before-diverging-arm-2.rs | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/tests/ui/nll/issue-27282-mutate-before-diverging-arm-2.rs b/tests/ui/nll/issue-27282-mutate-before-diverging-arm-2.rs new file mode 100644 index 000000000..9c3e7e997 --- /dev/null +++ b/tests/ui/nll/issue-27282-mutate-before-diverging-arm-2.rs @@ -0,0 +1,40 @@ +// This is testing an attempt to corrupt the discriminant of the match +// arm in a guard, followed by an attempt to continue matching on that +// corrupted discriminant in the remaining match arms. +// +// Basically this is testing that our new NLL feature of emitting a +// fake read on each match arm is catching cases like this. +// +// This case is interesting because it includes a guard that +// diverges, and therefore a single final fake-read at the very end +// after the final match arm would not suffice. +// +// It is also interesting because the access to the corrupted data +// occurs in the pattern-match itself, and not in the guard +// expression. + +struct ForceFnOnce; + +fn main() { + let mut x = &mut Some(&2); + let force_fn_once = ForceFnOnce; + match x { + &mut None => panic!("unreachable"), + &mut Some(&_) + if { + // ForceFnOnce needed to exploit #27282 + (|| { *x = None; drop(force_fn_once); })(); + //~^ ERROR cannot mutably borrow `x` in match guard [E0510] + false + } => {} + + // this segfaults if we corrupted the discriminant, because + // the compiler gets to *assume* that it cannot be the `None` + // case, even though that was the effect of the guard. + &mut Some(&2) + if { + panic!() + } => {} + _ => panic!("unreachable"), + } +} |